When you make an income from web sites, keeping the servers running is very important. I used to pay for a service that regularly checked my servers and alerted me with a text message to my phone when one of them went down. I abandoned that service for two reasons: first, I didn’t always get the alerts, and second, often the problem was connectivity at their network and nothing to do with me.

This week I found Alertra.com and I’m pleased to report that it solves these problems.
They avoid false alerts by rotating checks from eight different locations and not alerting you until three of the stations agree that the site is down.

The fees are reasonable, although they can add up if you’re monitoring lots of servers or sites. I’m using their HOST service, which monitors pretty much everything you need on a Web server: Ping, up to three HTTP ports, HTTPS, DNS, SMTP, POP3, IMAP4, FTP, SSH, TELNET, NNTP and up to three other TCP ports. Pricing varies depending on the monitoring frequency—I’m having my main server checked every 5 minutes and the secondary server every 30 minutes, and the total monthly fee for both is just over $30. A basic service to simply check your URL every 5 minutes is only $8.75 a month.

Alerts can be sent by email for free, or by SMS, pager, or voice phone for a small per-notification fee. I’m using the email notification to reach my cell phone, which avoids paying the SMS fee. You can set up a complex notification schedule if you want (for example, notify Bob at the first sign of downtime, and then notify Alice if the downtime lasts 60 minutes.)

I ran some tests by taking various services down in the middle of the night, and so far the alerts have been very prompt. My hosting provider has their own monitoring system, but this works much better, and an external monitor can spot problems in their network as well.